Golf club metallic head formation

Abstract

A wax shell covered pre-formed core body is provided, the thickness of the wax shell corresponding to the desired thickness of the wall structure. A ceramic shell is formed about the wax shell. The wax shell is removed by melting the wax, thereby to form an opened gap between the ceramic shell and the core body. Molten metal is cast into the opened gap, thereby to form the wall structure extending about the core body and at the sole, while forming and maintaining port structure through the wall structure and spaced from the sole, and allowing the wall structure to solidify to form the head. The ceramic shell is removed from the wall structure, and the core body is removed from the interior of the solidified head, and via the port structure.

I claim: 
     
       1. In the method of forming a hollow metallic golf club head having wall structure defining a front wall, a heel, a toe, a rear wall, a sole, and a top wall, the steps that include: a) providing a wax shell covered pre-formed core body, the thickness of the wax shell corresponding to the desired thickness of said wall structure,   b) forming a ceramic shell about the wax shell,   c) removing the wax shell by melting the wax, thereby to form an opened gap between the ceramic shell and the core body,   d) and casting molten metal into the opened gap, thereby to form said wall structure extending about the core body and at the sole, while forming and maintaining a rearward port structure through said rear wall formed by said wall structure and spaced from the sole, said port structure formed directly rearwardly of the main extent of said core body, and allowing said wall structure to solidify to form the head,   e) removing said ceramic shell from said wall structure, and removing said core body from the interior of said solidified head, and via said rearward port structure.   
     
     
       2. The method of claim 1 wherein said core body is ceramic. 
     
     
       3. The method of claim 2 including passing a tool through said port structure and into said interior of the head to break up said ceramic core body into small pieces. 
     
     
       4. The method of claim 1 wherein said port structure is formed to have an overall size substantially less than the overall size of said sole. 
     
     
       5. The method of claim 1 wherein said port structure is formed as multiple ports through said head rear wall. 
     
     
       6. The method of claim 1 including closing said port structure by providing and attaching metallic closure structure over said port structure. 
     
     
       7. The method of claim 5 including closing said multiple ports by providing and attaching metallic closures over said multiple ports. 
     
     
       8. The method of claim 1 including providing spacer means to extend in said cavity between said ceramic shell and said core body. 
     
     
       9. The method of claim 1 wherein said sole is formed to define a medial ridge and two dished recesses at opposite sides of said ridge, said multiple ports formed rearwardly of said dished recesses. 
     
     
       10. The method of claim 1 wherein said core body is provided to define an elongated recess sunk in the surface of the core body and corresponding to an elongated stiffener rib to be formed by said head wall structure at the interior side thereof. 
     
     
       11. The method of claim 10 including forming said multiple ports to extend through said head rear wall at opposite sides of a plane defined by said stiffener rib. 
     
     
       12. The method of claim 1 including providing multiple core body positioning ceramic stand-offs to extend in said gap between said core body and said ceramic shell. 
     
     
       13. The method of claim 12 wherein said stand-offs are provided during the formation of said ceramic shell about the wax shell. 
     
     
       14. The method of claim 1 wherein said wax shell covered core body is provided by: i) providing a pre-formed core body having the general shape of the head,   ii) positioning said body within a cavity formed by mold structure thereby to provide an initial gap about the core body,   iii) and filling wax into said initial gap to cover the core body and to form said wax shell.   
     
     
       15. The method of claim 14 including forming an elongated recess sunk in the surface of the core body and corresponding to an elongated stiffener rib to be formed by said head wall structure at the interior side thereof. 
     
     
       16. The method of claim 15 including forming said rib to extend substantially in a loop that extends forwardly and rearwardly with respect to the head wall structure to be formed. 
     
     
       17. The method of claim 1 including forming said rearward port structure to have cross sectional area less than 0.5 square inches.